1. Field of the Invention
The present invention relates generally to infant and toddler's protective devices and in particular to a child restraint devices designed for attachment to a vehicle seat such as an aircraft passenger seat.
2. Description of the Prior Art
Child restraint devices have basically been designed for use in privately owned passenger automobiles. This use is limited to normally one or two children over the useful life of the restraint device. Furthermore, the restraint device is designed for long stable placements in normally one or two automobiles. As the restraint device is intended for long stable placements, relatively routine removal and replacement of the attached device in a passenger seat is generally a cumbersome process.
Examples of previous restraint devices include U.S. Pat. No. 4,040,664 issued to Tanaka et al. for a "Harness Anchoring for Child Safety Seat": U.S. Pat. No. 3,709,558 issued to Jakob for a "Child Safety Seat"; U.S. Pat. No. 3,992,040 issued to Gannac for a "Safety Harness for Use By a Child In a Vehicle"; U.S. Pat. No. 3,321,247 issued to Dillender for a "Child's Safety Harness"; U.S. Pat. No. 3,301,594 issued to Pukish for a "Safety Harness"; and U.S. Pat. No. 3,125,375 issued to Bird et al. for a "Safety Seat Harness for Vehicle".
Between forty thousand (40,000) to fifty thousand (50,000) children under the age to two (2) travel by airplane daily in the United States. Current Federal Aviation Administration (FAA) rules allow children under the age of two (2) to be retained in parents' laps, which obviously provides little, if any, protection to the child during an accident or in an emergency situation. Recent studies found that placing unrestrained children on the lap of an adult is "likely to promote fatalities and injuries to these children in an impact situation." Additionally, supplementary restraints for lap held children was found to possibly "promote other injuries due to the manner in which the restraining forces are transmitted to the children."
Performance standards for child restraint systems sold in the United States are defined by Federal Motor Vehicle Safety Standard 213 (FMVSS-213) . Performance criteria of child restraint systems installed in airplane seats should at least provide the level of protection implied in the government standards and test procedures by which they are approved. These criteria include protection from serious injury to the head, chest, and legs.
Conventional restraint devices used for automobiles are inadequate for use with existing aircraft seats. There are important differences between airplane and automobile seats. The main problem is the fact that the anchor point for an automobile seat is located generally aft and below the point where the back and sitting portion of the frame members meet. As seen in FIG. 1, a back mounted conventional car restraint device 400 is shown attached to a conventional airline passenger seat 300 by the insertion of seat belt 180 through a slot 402. With this attachment, the attachment point of the car restraint device 400 is adjacent to a center of gravity 403 of the secured child which prevents significant, if any, vertical movement of restraint device 400. However, the attachment angle is approximately one hundred and ten (110.degree.) degrees, which places the attachment point too far back for safety purposes. Thus, in an airline accident, car restraint device 400 is not secured tightly, relative to the imposed horizontal vector, and can move translationally (horizontally), as indicated by arrow T, at least six (6) inches creating an unsafe condition for the child secured within car restraint device 400.
A "below the knee" mounted car restraint device 450 is shown attached to a conventional airline passenger seat 300 by the insertion of seat belt 180 through a slot 452 (FIG. 2). With this attachment, the attachment point of the car restraint device 450 is below a center of gravity 453 of the secured child. Furthermore, the attachment angle is approximately twenty (20.degree.) degrees, which places the attachment point too far forward for safety purposes. Thus, in an airline accident, car restraint device 450 is not secured tightly relative to the vertical vector and can move rotationally, as indicated by arrow R, creating an unsafe condition for the child secured within car restraint device 450.
FAA's studies have shown that conventional car seats perform poorly in simulated aircraft accidents. Present automotive standards allow for forward head translation of thirty two (32) inches, but considering current aircraft seat pitches, the proper limit for an aircraft device should be closer to twenty four (24) inches. Seat belts 180 used for existing aircraft are positioned approximately 10 inches forward from the point that the automobile seat belts are located. Thus, if aircraft seat belt 180 is inserted through the slot in the back portion of the conventional restraint device a tight attachment of the device to the aircraft seat is not possible.
Thus, during an accident the loose attachment of a conventional car restraint device to an aircraft passenger seat, would cause the restraint device to rotate or travel forward, via rotational or translational forces acting on the aircraft passenger seat. This scenario could possibly cause the child or infant disposed therein to hit his or her head against the food tray or seat disposed in the row in front of the infant or child. Accordingly, conventional restraint devices can not be sufficiently anchored to prevent a child's head from striking the seat ahead. As such, too much forward or rotational movement is allowed. Even when the forward or rotational movement is within federal standards of thirty two (32) inches, a child's head can still hit the seat ahead.
According, to FAA document No. DOT/FAA/AM-94/19 entitled "The Performance of Child Restraint Devices in Transport Airplane Passenger Seats" dated September 1994 (hereinafter referred to as the "FAA Report"), lap belts for automobiles are attached at locations that are geometrically different from a typical airplane passenger seat. Inboard and outboard belt anchor points 602 and 604, respectively, on an automotive seat 600 are at different heights (FIG. 17). A line passing through the belt anchor points is not parallel to the lateral line defined by a seat back pivot axis 606. The lap belts on an airplane seat 700 are usually located near a horizontal lateral line passing through a cushion reference point 702 (FIG. 16). This difference results in a more vertical lap belt path over the restraint device in the airplane seat.
Automotive seat backs do not rotate forward in a manner representative of airplane passenger seats during impact. See FAA report which is incorporated by reference as if fully set forth herein. Airplane passenger seats commonly have breakover seat backs as a convenience feature. On seats with breakover backs, the seat back can be rotated forward to a horizontal position by pushing on the seat back, nominally with thirty (30) pounds of force applied at the top of the seat back. The combined effects of breakover seat backs and aft row occupant impact forces transferred through the seat back in an accident situation were not evaluated by FMVSS-213 when the current standards were adopted.
Additional problems with the use of conventional restraint devices is that modern automobile restraints use a short fixed-length strap on one side. The tension of the belts and shoulder straps is automatically adjusted by the retractor mechanism in the inertia reel. Typically, an automobile buckle is positioned to the inboard side of the occupant when in use. See FAA Report. Airplane passenger seat belts are manually adjusted, and the range of adjustment is limited. The buckle on an airplane passenger seat is centered over the lower abdomen when adjusted by an adult occupant.
Another problem is that the available lateral space for the installation of a child restraint device on airplane seats is limited to the distance between the arm rests. Typically, this distance is 16.5 to 17.5 inches on economy class seats. On most economy class seats the arm rests can be raised to stowed position which provides additional space. However, seats in some rows have non-stowable arm rests. See FAA Report. Thus, space requirements are also an important consideration for the child restraint device.
The FAA Report found that conventional forward facing restraint devices were unacceptably loose when attached to an airplane passenger seat due to vertical path of the lap belt securing the device to seat. The vertical path of the lap belt is created by the lap belt anchor point of the airplane seat. During testing, the restraint device was able to move forward approximately six (6) inches, even with the lap belt adjusted to its minimum length. See FAA Report. This loosely secured conventional child restraint device resulted in poor performance during testing and could cause serious injury in use. The FAA report labeled the poor interface with airplane lap belts which resulted in a very loose fit as a "misuse condition."
The attachment of the conventional child restraint device to the airplane seat results in a nearly vertical angle of the airplane lap belts that secures the child restraint device. When installed, the lap belt path angle from the airplane seat attachment to the child restraint device ranged from approximately eighty five (85.degree.) to ninety three (93.degree.) degrees above horizontal. This vertical load path does not produce an effective restraint of forward motion. See FAA Report. An angle greater than ninety (90.degree.) degrees means the seat belt anchor is forward of the child restraint device's belt path. During horizontal impact conditions, the child restraint device must translate forward until the belt path angle is significantly less than ninety (90.degree.) degrees for belt tension forces to restrain the child restraint device. Accordingly, use of a conventional child restraint device on airplane passenger seats creates an undesirable and dangerous condition.
The FAA Report also found conventional harnesses and backless booster seats to also be dangerous for aviation use. The harnesses also allowed too much room for movement. It was found that due to the limited adjustment range and anchor location of the airplane seat lap belts, the harness restraint could not satisfactorily restrain the motion of a typical three (3) year old child. See FAA Report. The loose tensions of the lap belts did not provided a secure restraint utilizing the harness. As to booster seats, airline seat backs, are designed to rotate forward. As the child booster seat are backless, in a crash a child could be crushed between the booster seat and the seat back. The FAA Report also found that the booster seat could not be correctly installed in an airplane seat and that the child occupant could be exposed to potential abdominal injury due to the combined effects of forces imparted from the aft row occupant and the seat back breakover.
The FAA Report concluded that the performance of certain types of child restraint devices, currently available, do not enhance the level of safety for children in transport airplane passenger seats and that the expectation of equivalent protection for children restrained in certain types of child restraint device traveling by automobile can not be met in an airplane seat. FAA Report, Page 27. One of the stated reasons for these negative results is that the restraint devices are designed to meet automotive requirements, which do not necessarily adapt properly to an airplane seat. Airplane seat belts differ in anchor point geometry, tension adjustment, and buckle hardware. The lap belt anchor point geometry on airplane seats does not afford effective restraint of forward excursion of the occupant with this type of child restraint. These differences adversely affect the performance of child restraint devices designed primarily for the automobile interior.
Additionally, conventional aft facing child restraint devices also have the problem of interfering with passage between the seat rows and the recline motion of a forward row seat due to the forward overhang of the aft facing restraint.
Furthermore, any modification to any part of an aircraft requires extensive testing to be performed per strict aviation regulations. This is in addition to the cost and time which is involved for such testing and modifications of a new aircraft seat, as well as the time involved in obtaining governmental approval. Thus, the possibility of changing the position of seat belts on existing airline passenger seats, to make use with car restraint devices safe, is not practical.
Accordingly, what is needed in the art, is a child restraint device which can be safely utilized with an existing aircraft passenger seat and lap belt in either a forward facing orientation or an aft facing orientation, and without modification to the aircraft seat or lap belt. It is therefore, to the effective resolution of the aforementioned problems and shortcomings that the present invention is directed.